RDMA, core and ULPs: Declare ib_post_send() and ib_post_recv() arguments const

Since neither ib_post_send() nor ib_post_recv() modify the data structure
their second argument points at, declare that argument const. This change
makes it necessary to declare the 'bad_wr' argument const too and also to
modify all ULPs that call ib_post_send(), ib_post_recv() or
ib_post_srq_recv(). This patch does not change any functionality but makes
it possible for the compiler to verify whether the
ib_post_(send|recv|srq_recv) really do not modify the posted work request.

To make this possible, only one cast had to be introduce that casts away
constness, namely in rpcrdma_post_recvs(). The only way I can think of to
avoid that cast is to introduce an additional loop in that function or to
change the data type of bad_wr from struct ib_recv_wr ** into int
(an index that refers to an element in the work request list). However,
both approaches would require even more extensive changes than this
patch.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

3 files changed, 19 insertions, 14 deletions

diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h b/drivers/infiniband/hw/hns/hns_roce_device.h
index ceb490c732c0..1c252753fb12 100644
--- a/drivers/infiniband/hw/hns/hns_roce_device.h
+++ b/drivers/infiniband/hw/hns/hns_roce_device.h
@@ -763,10 +763,10 @@ struct hns_roce_hw {
 			 int attr_mask, enum ib_qp_state cur_state,
 			 enum ib_qp_state new_state);
 	int (*destroy_qp)(struct ib_qp *ibqp);
-	int (*post_send)(struct ib_qp *ibqp, struct ib_send_wr *wr,
-			 struct ib_send_wr **bad_wr);
-	int (*post_recv)(struct ib_qp *qp, struct ib_recv_wr *recv_wr,
-			 struct ib_recv_wr **bad_recv_wr);
+	int (*post_send)(struct ib_qp *ibqp, const struct ib_send_wr *wr,
+			 const struct ib_send_wr **bad_wr);
+	int (*post_recv)(struct ib_qp *qp, const struct ib_recv_wr *recv_wr,
+			 const struct ib_recv_wr **bad_recv_wr);
 	int (*req_notify_cq)(struct ib_cq *ibcq, enum ib_cq_notify_flags flags);
 	int (*poll_cq)(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc);
 	int (*dereg_mr)(struct hns_roce_dev *hr_dev, struct hns_roce_mr *mr);
diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v1.c b/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
index ae6b642ec073..8e11c6b62009 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
+++ b/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
@@ -58,8 +58,9 @@ static void set_raddr_seg(struct hns_roce_wqe_raddr_seg *rseg, u64 remote_addr,
 	rseg->len   = 0;
 }
 
-static int hns_roce_v1_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
-				 struct ib_send_wr **bad_wr)
+static int hns_roce_v1_post_send(struct ib_qp *ibqp,
+				 const struct ib_send_wr *wr,
+				 const struct ib_send_wr **bad_wr)
 {
 	struct hns_roce_dev *hr_dev = to_hr_dev(ibqp->device);
 	struct hns_roce_ah *ah = to_hr_ah(ud_wr(wr)->ah);
@@ -342,8 +343,9 @@ out:
 	return ret;
 }
 
-static int hns_roce_v1_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,
-				 struct ib_recv_wr **bad_wr)
+static int hns_roce_v1_post_recv(struct ib_qp *ibqp,
+				 const struct ib_recv_wr *wr,
+				 const struct ib_recv_wr **bad_wr)
 {
 	int ret = 0;
 	int nreq = 0;
@@ -993,7 +995,8 @@ static int hns_roce_v1_send_lp_wqe(struct hns_roce_qp *hr_qp)
 {
 	struct hns_roce_dev *hr_dev = to_hr_dev(hr_qp->ibqp.device);
 	struct device *dev = &hr_dev->pdev->dev;
-	struct ib_send_wr send_wr, *bad_wr;
+	struct ib_send_wr send_wr;
+	const struct ib_send_wr *bad_wr;
 	int ret;
 
 	memset(&send_wr, 0, sizeof(send_wr));
diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
index a9bc6b279175..25e0407d3f31 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
+++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
@@ -103,7 +103,7 @@ static void set_extend_sge(struct hns_roce_qp *qp, const struct ib_send_wr *wr,
 static int set_rwqe_data_seg(struct ib_qp *ibqp, const struct ib_send_wr *wr,
 			     struct hns_roce_v2_rc_send_wqe *rc_sq_wqe,
 			     void *wqe, unsigned int *sge_ind,
-			     struct ib_send_wr **bad_wr)
+			     const struct ib_send_wr **bad_wr)
 {
 	struct hns_roce_dev *hr_dev = to_hr_dev(ibqp->device);
 	struct hns_roce_v2_wqe_data_seg *dseg = wqe;
@@ -164,8 +164,9 @@ static int set_rwqe_data_seg(struct ib_qp *ibqp, const struct ib_send_wr *wr,
 	return 0;
 }
 
-static int hns_roce_v2_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
-				 struct ib_send_wr **bad_wr)
+static int hns_roce_v2_post_send(struct ib_qp *ibqp,
+				 const struct ib_send_wr *wr,
+				 const struct ib_send_wr **bad_wr)
 {
 	struct hns_roce_dev *hr_dev = to_hr_dev(ibqp->device);
 	struct hns_roce_ah *ah = to_hr_ah(ud_wr(wr)->ah);
@@ -530,8 +531,9 @@ out:
 	return ret;
 }
 
-static int hns_roce_v2_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,
-				 struct ib_recv_wr **bad_wr)
+static int hns_roce_v2_post_recv(struct ib_qp *ibqp,
+				 const struct ib_recv_wr *wr,
+				 const struct ib_recv_wr **bad_wr)
 {
 	struct hns_roce_dev *hr_dev = to_hr_dev(ibqp->device);
 	struct hns_roce_qp *hr_qp = to_hr_qp(ibqp);